Bomb braking system



M r h 25, 1969 F. SCHROTH 3,434,417

BOMB BRAKING SYSTEM Filed April 5, 1967 Sheet of 4 Fig.5

/ To 3i INVENTOR. F: 5 ch 1* 0 25/7 BY m d u gall! ATTORNEBS March 25,1969 F. SCHROTH 3,434,417

BOMB BRAKING SYSTEM Filed April 5. 1967 Sheet 2 of 4 ifig 7 INVENTOR.

F. Sch/"off;

ELJ Q guin- ATTO VLN E as March 25, 1969 F. SCH ROTH 3,434,417

BOMB BRAKING SYSTEM Filed April 3. 1967 Sheet 3 of 4 INVENTOR.

dlwwou ATTOY N E35 F- SCHROTH March 25, 1969 BOMB BRAKING SYSTEM Sheet 4of 4 Filed pril 5, 1967 INVENTOR. 5 C /7 ro'bh A-r'romueg United StatesPatent 01 fee 3,434,417 BOMB BRAKING ,SYSTEM Fridolin Schroth, Koblenz,Germany, assignor to Les Forges de Zeebrugge S.A., Herstal-lez-Liege,Belgium, a company Filed Apr. 3, 1967, Ser. No. 628,072 Claims priority,application Germany, July 26, 1966, Sch 39,315; Dec. 24, 1966, Sch40,023 Int. Cl. F42b 25/00 US. 'Cl. 102-4 4 Claims ABSTRACT OF THEDISCLOSURE An air dropped missile has a nose provided with outertransverse corrugations and a nose-shaped cover adapted to momentarilycover these corrugations and having a smooth outer surface.

This invention relates to a system provided for braking a bomb releasedat low altitude and at high speed.

As is known, bombs are most etficiently released when flying in skimmingthe ground at high speed. This method has the advantage of littleendangering the attacking plane since it is under radar reach of theenemy. The shooting accuracy realizable when attacking in skimming theground is very high since the bombs may be released at a very smallheight above the target. In addition, the bombs may be so released evenin disadvantageous atmospheric conditions. However, a normal unbrakedbomb released in skimming the ground at high speed endangers the planeitself. So as not to endanger the plane by said bomb, the latter shouldbe provided with a braking rocket. However, a braking rocket introducesat least the following drawbacks:

1) In case of light structural targets, the bomb ricochets and iswithout any effect;

(2) In case of bulky structural targets, the bomb will break up by thehigh speed without having fulfilled its function.

Various relatively complicated systems have been designed, said systemsbeing provided to allow releasing bombs in skimming the ground withoutendangering the plane and the crew thereof.

A first systembrakes the bomb after releasing from the plane by means ofa parachute provided at the rear of the bomb. In another system, thebraking is provided by a combination of spacing traps and a parachute.Still in another system, the bomb is braked only with spacing traps.

These three braking systems are too complicated and subject to defectsand, when suddenly opening the braking device, the impact is too high.In addition, a sudden braking of the bomb has a unfavorable influenceupon the aiming accuracy.

This invention is based upon the new concept of a simple and flexiblebraking of the bomb.

For that purpose, the invention provides conditioning the bomb body on alongitudinal portion from the front end so as to present a not smooth ornot continuous external surface, i.e. a surface having successive stepsgenerally in the form of annular grooves. Generally, these grooves willbe equally spaced and they may have an essentially variablecross-section in shape as well as in size, the latter being determinedand selected in accordance with the desired braking effects as afunction of the projectile type being equipped. This special brakingsurface may be provided either by the corresponding portion of the bombbody itself or by an inserted casing. The latter will be conditioned tobe readily disposed upon the bomb without any tool and without any longor critical opera tion and without requiring any modification in the ex-3,434,417 Patented Mar. 25, 1969 ternal characteristics of the bomb orits fastening or suspending means. For that purpose, along a generatrixand at least upon a longitudinal portion thereof from its largerdiameter, thesaid casing will be provided with such a longitudinalcut-out that the said casing will be capable of substantially coveringinstantaneously the front portion of the bomb by avoiding the obstaclepresented by the suspension rings thereof.

According to the invention, means are also provided to cancel thebraking effects of the so conditioned bomb either when such braking isnot required or before releasing. This means comprises covering the saidunsmooth surface with a cap having a smooth external surface. Thus,according to the case, this cap will be disposed either directly uponthe corresponding front portion of the projectile or concentrically uponthe cap having an unsmooth external wall. In any case, the said caphaving a smooth external wall will be conditioned to be eithersystematically separable from the projectile or spaced from the saidunsmooth external surface of the said projectile when releasing orimmediately thereafter. The unsmooth portion will be freed in thismanner either by a connection between the said cap having a smoothexternal Wall with a portion adjoining the plane or by separating theconstituting portions of the said cap by means of an explosive chargeprovided or not provided with a retarding system or by any other means.

Thus, this invention concerns bombs, the external surface of which isnot smooth upon a longitudinal portion from the front end, i.e. bombshaving a braking surface, and any cap having an external braking surfaceconditioned to be secured on the front portion of a bomb, andcomplementary caps having a smooth external surface to be momentarilysecured either directly on the bomb or on the cap covering the frontportion of the bomb.

Only by way of example and without any restriction, embodiments will bedescribed hereafter and represented in the enclosed drawings wherein:

FIGURE 1 shows a plan view of a bomb covered with a casing according tothe invention;

FIGURE 2 is an end view according to the arrow F2 of FIGURE 1;

FIGURE 3 shows a half vertical section and a half longitudinal sectionof a casing according to the invention;

FIGURE 4 is an end view in the direction of arrow F4 of FIGURE 3;

FIGURES 5, 6 and 7 show, in cross-section and by way of example, threedifferent profiles of annular grooves characterizing the casingaccording to the invention;

FIGURE 8 shows a plan view of a bomb, the front portion of whichpresents a braking surface;

FIGURE 9 shows a half plan view and a half longitudinal section of acomplementary cap for momentarily cancelling the braking effects FIGURE10 shows a partial plan view and a partial longitudinal section of theapplication of a cap according to FIGURE 9 on a bomb covered with asleeve having an unsmooth surface according to FIGURE 1;

FIGURE 11 shows a partial plan view and a partial longitudinal sectionof the application of a cap according to FIGURE 9 on a bomb according toFIGURE 8; and

FIGURE 12 is a view similar to that of FIGURE 11 representing anotherembodiment for realizing and mounting the cap according to FIGURE 9.

As represented in FIGURES l to 4, a casing 1 according to the inventionis generally made of a plastic material or any other suitable materialunder the form of a cap capable of correctly contouring the frontportion of bomb 2 at least upon a predetermined length L. The internalface 3 of said cap will be generally smooth and, in any case, it will bedetermined in accordance with the corresponding portion of bomb 2,whereas the external surface 4 of said cap will present successive stepsgenerally outlined by similar or different, equally spaced ordifferently spaced annular grooves 5 in accordance with the brakingeffect being produced.

According to FIGURES l, 3 and 5, the said external surface 4 will betransversely corrugated so that the said annular grooves 5 andconsequently also the annular ribs 6 separating them will besinusoidally shaped. FIGURE 6 represents an ear shape and FIGURE 7represents such ear shape slightly modified. Of course, any othersuitable shape could be provided. This raised surface portion extendsupon a length L of the casing, said length being itself predetermined inaccordance with the braking effects being produced. The rear portion 7of casing 1 may be smooth, respectively continuous or cylindrical. Uponthe whole length L or a portion thereof, the casing presents alongitudinal cut-out 8 the width E of which is equal or slightly largerthan the diameter of the fastening or suspension rings 9 generallyprovided on bomb 2. Of course, this cut-out may be adjusted inaccordance with the space occupied by the said fastening elements of thebomb so that the casing may be disposed upon the bomb without any toolnor any disassembling operation.

When applying such casing 1, the cross-section of the bomb is increasedand due to this increase and the effect of the external profile of saidcasing, the friction resistance is substantially increased.Consequently, the falling time of the bomb after releasing is increased,which is sufficient to give a sufficient safety distance to the plane.By means of such casing forming a very simplified braking means, thesame effects as those provided by using complex and expensive brakingmeans are obtained.

This braking casing may be fitted to any bomb before loading and it maybe secured to said suspension rings 9 of the bomb without anydisassembling or mounting operation of any portion of the bomb.

According to the present invention, the guiding mechanism is keptintegral with the bomb. In addition, due to the effect of thelongitudinal cut-out 8 extending advantageously as a groove 10 up to thenose of the bomb, owing to the back pressure when releasing, the bombhas a tendency to nose-drive, thereby bringing it more rapidly andsystematically in its vertical position for a normal fall.

Of course, the same braking effect may be obtained by making the bomb asrepresented by way of example in FIGURE 8, the front portion presentinga profile similar to the profile 4 of the sleeve described in thepreceding example. The same successive parallel grooves 5 andtorus-shaped ribs 6 are also provided therein.

Whatever the embodiment may be, provided that the braking effect is notrequired, the said unsmooth surfaces 4 may be advantageously coveredwith a cap 11 having a smooth external surface. This cap will beconditioned so that its shape and its internal dimensions allow anadjustment by leaning upon the outermost generatrices of said steppedribs 6.

As described for the cap having an unsmooth external surface, thiscomplementary cap may have, a length L, L or any other length consistentwith the bomb type and the used separating means.

In one embodiment, this complementary cap 11 may be connected e.g. by atleast a filiform element having a good resistance with an adjoiningportion of the plane in such manner that, due to the effect of the speeddifferences immediately after releasing the bomb from the plane, thesaid cap with a smooth external wall is separated from the projectile.Alternately, the said cap having a smooth external wall could bearranged with shells being kept assembled by a means freed whenreleasing. A modification of this embodiment is represented in FIGURE 12accorring to which the complementary cap 11 is provided in four sectionsthree of which 12-13-14 are apparent, each section being hinged on thebomb body as indicated in 15. These four sections are kept in coveringposition by any suitable means such as weld spots which are broken byfiring an explosive charge 16 under the action of the releasingmechanism of the bomb and preferably provided with a retarding device.After the explosion of charge 16, the said sections occupy the positionindicated in dotted lines in FIGURE 12, a position in Which they provideadditional guiding surfaces 17 and complementary braking surfaces 18.

For any cap having a smooth or unsmooth external wall, there may be usedany suitable material such as metal, pressed material, fibrous material,plastic material or a combination thereof.

What I claim is:

1. An air dropped missile comprising a body having a nose, at least apart of the outer surface of said nose having transverse corrugations,and a separate noseshaped cover adapted to momentarily cover saidcorrugations and having a smooth outer surface.

2. A missile in accordance with claim 1, wherein said nose is a separatemember secured to the forward end of said body.

3. A missile in accordance with claim 2, wherein said cover consists ofa plurality of assembled parts.

4. A missile in accordance with claim 3, wherein the parts of said coverare pivoted to said body.

References Cited UNITED STATES PATENTS 2,393,274 l/1946 Whitesell 102-23,002,453 10/1961 Fedor et al 102-2 3,112,906 12/1963 Zeyher 102-4 X3,185,035 5/1965 Gregory-Humphries 89-1.816 X 3,282,216 11/1966 Calfeeet al 102-105 3,298,312 1/1967 Adams 102-105 FOREIGN PATENTS 2,271 1895Great Britain.

SAMUEL W. ENGLE, Primary Examiner.

US. Cl. X.R. 244-327

